cdhc lib: add statlib cdh fortran code to lib docs

[nilason]

This PR aim to add the Fortran source code, which was a base for cdhc library, for documentation purposes in the form of a Markdown file.

This is the source the library's author Darrell McCauley mention in "Goodness of Fit Tests" (lib/cdhc/docs/goodness.pdf):

Each function in the library returns a pointer to static double. The cdhc library was inspired by Johnson’s STATLIB collection of FORTRAN routines for testing distribution assumptions [22]. Some functions in cdhc are loosely based on Johnson’s work (they have been completely rewritten, reducing memory requirements and number of computations and fixing a few bugs). Others are based on algorithms found in Applied Statistics, Technometrics, and other related journals.

Limited amount of documentation remains, links mentioned in https://lists.osgeo.org/pipermail/grass-user/1995-July/023710.html are no longer available, thus this addition might be of help in the future.

[neteler]

(hint: to see this PR rendered in Markdown, see

Tab "Files changed" > three-dots menu on the right > View file

which is currently this:
https://github.com/OSGeo/grass/blob/f511591b948c1e0731156ad62a19ec1267623827/lib/cdhc/doc/chd_statlib.md)

[echoix]

Looks ok to me, it’s a doc-only change, and is justified to be here for posterity.

[neteler]

it’s a doc-only change

In this case, with only a markdown file change, I would expect all CI build jobs being skipped. But indeed they all run (effectively not generating any insights):

I ask because of the meanwhile closed issue #2174.

[nilason]

it’s a doc-only change

In this case, with only a markdown file change, I would expect all CI build jobs being skipped. But indeed they all run (effectively not generating any insights):

I ask because of the meanwhile closed issue #2174.

Technically adding [skip ci] to commit description work by default on GH to avoid CI checks. The rebase commit message ("Merge branch 'main' into cdhc_add_fortran") didn't contain that tag. For that to work now it had to be eg. "Merge branch 'main' into cdhc_add_fortran [skip ci]".

[echoix]

We have some checks that apply to markdown, docs and more, so it still makes sense to have some run.